Diseases in growing plants are well known. Such diseases have resulted in substantial food and economic loss to farmers for many years. Farmers often combat such diseases using harsh techniques including sacrificing one or more infected plants by burning, cutting or other destructive measures. In the past, diseases of growing plants have been treated using a variety of chemical materials including toxic metals, organic fungicides or herbicides. These compositions have had some effect in alleviating plant disease. Many of these materials are contacted with the plant through fogging, spraying or injection of the material into the soil surrounding the plant. Such treatments typically tend to concentrate the active material on the surface layers of the fruit, leaf, stem or root in the plant with an eye towards preventing the introduction of infective microorganisms through the protective outer layers of the plant surface. The outer layers of fruit, leaf, stem and root often have protective measures that attempt to prevent the attack by fungi and other active microorganisms on plant tissues. Such chemical treatments have had some success, however, the use of toxic metals, organic fungicides and other toxic materials are dangerous to the user and often pose an environmental challenge and can cause undesirable effects in killing other beneficial organisms.
Peroxy compounds; notably, peroxy acid/hydrogen peroxide compositions, are well known in the prior art as sanitizing materials. Particularly, the Grosse Bowing patents, U.S. Pat. Nos. 4,051,058 and 4,051,059, disclose basic formulation materials in stabilizing peroxy acetic acid/hydrogen peroxide compositions using sulfonate or phosphonate stabilizing agents. The prior art regarding the use of these materials has developed actively. Also, the Grosse Bowing patents describe stabilized peracid materials using sulfonate and phosphonate stabilizing agents. Sennewald et al., U.S. Pat. No. 3,442,937, describes quinolin polyphosphate or urea stabilized peracid solutions. Malone et al, U.S. Pat. No. 5,565,213, describe stabilization of water containing high concentration of sugar materials. Richards et al, U.S. Pat. No. 5,597,791, describe gelled or colloidal peracid treatment compositions. These materials have applications as surface cleaners, detergent, bleaches, automatic dishwashing formulations and similar.
Lokkesmoe et al., U.S. Pat. No. 5,122,538, describe a specialized peroxy acid generator apparatus used to make percarboxylic acid materials. Schmidt, U.S. Pat. No. 5,139,788, describes an antimicrobial composition. Oakes, U.S. Pat. No. 5,200,189, describes peroxy acid antimicrobial compositions. Lokkesmoe, U.S. Pat. No. 5,409,713, describes a process for inhibiting microbial growth in aqueous transport systems contaminated with substantial proportions of food waste, dirt and other agricultural by-products. Richter, U.S. Pat. No. 5,436,008, describes sanitizing compositions. Hei et al, U.S. Pat. No. 5,567,444, describe potentiated aqueous ozone containing cleaning and sanitizing compositions using ozone in combination with materials that enhance cleaning properties. Hei, U.S. Pat. No. 5,858,443, describes methods for effective microbial control in reducing slime in hard surfaces common in food processing equipment using in line ozone injection. Holzhauer et al., U.S. Pat. Nos. 5,472,619 and 5,647,997 describe the use of peracetic acid materials in purification of highly contaminated waste waters. Such waste waters are contaminated with substantial proportions of food waste which are typically skimmed prior to treatment. These food contaminated wastes are different than waters commonly found in decorative, recreational or sporting loci. Lastly, Robertson et al., U.S. Pat. No. 5,395,530, describe using a combination of a toxic biocide and an enzyme for destroying filamentous bacteria.
Huss et al, PCT WO 97/08100, describe the use of peracetic acid materials to disinfect large quantities of waste water such as waste water containing substantial concentration of food waste, brewery waste, dairy waste, effluent or sludge from municipal sewage works or other contaminated material. Commonly, such peroxy materials are used by contacting soiled or contaminated surfaces with the peracid material for the purpose of substantially reducing harmful populations of microorganisms on the surface. The art recognizes that these peracid materials have substantial utility in killing microorganisms.
Similarly, the art has recognized that hydrogen peroxide, peroxy acid/hydrogen peroxide, peracetic acid/hydrogen peroxide materials can be useful in reducing harm to growing plants by the topical application of such materials on the exterior surfaces of plant, bud, fruit, leaf, stem and root. Representative examples of the known technology in this area include Soyez, PCT WO 95/28840; Goebel et al., EP 35800; Lippert, DK 9300538; Otsuka, JP 7031210; Otsuka, JP 7258005; Langford, EP 242990; Wright et al., PCT WO 94/06294; Larose et al., U.S. Pat. No. 5,723,406; and Hoffman et al., U.S. Pat. No. 5,162,052. This body of art describes that growing plants can be treated with a variety of anti-plant disease agents by applying the agent topically or in a controlled release mode to the surface of the plant leaf, stem or root. We have found that such chemical treatments to the exterior of plant tissue often are insufficient to obtain sufficient protection from plant disease to the growing plant. We believe that the reduced efficacy of these materials is substantially related to the fact that the active components in the hydrogen peroxide, hydrogen peroxide/peroxy compound, hydrogen peroxide peracetic acid compounds are prevented from attacking pathological microorganisms within the plant because they are limited to the surface of the plant by the protective layers of the plant structure. Our testing shows that simple topical application of the materials to plants can often result in the loss of the plant completely and spread of contagion to neighboring plants.
A substantial need exists for methods of treating growing plants, particularly plants having an active transpiration layer that can operate to protect growing plants from the undesirable effects of infective microorganisms.